In electronic devices such as display units, a function section including an electronic circuit, a display body, and other components is provided on a substrate surface. In a case where the substrate surface has detects such as a scratch and a dent, in order to reduce damage to the electronic circuit it is desirable to repair such defects before formation of the electronic circuit. For example, in Patent Literature 1, it is proposed that a restoration material is injected onto a substrate surface such as glass having defects such as a scratch and a dent and is hardened, and thereafter, the hardened restoration material is locally polished to planarize the substrate surface.